RESUMO
Biological structures are defined by rigid elements, such as bones, and elastic elements, like muscles and membranes. Computer vision advances have enabled automatic tracking of moving animal skeletal poses. Such developments provide insights into complex time-varying dynamics of biological motion. Conversely, the elastic soft-tissues of organisms, like the nose of elephant seals, or the buccal sac of frogs, are poorly studied and no computer vision methods have been proposed. This leaves major gaps in different areas of biology. In primatology, most critically, the function of air sacs is widely debated; many open questions on the role of air sacs in the evolution of animal communication, including human speech, remain unanswered. To support the dynamic study of soft-tissue structures, we present a toolkit for the automated tracking of semi-circular elastic structures in biological video data. The toolkit contains unsupervised computer vision tools (using Hough transform) and supervised deep learning (by adapting DeepLabCut) methodology to track inflation of laryngeal air sacs or other biological spherical objects (e.g., gular cavities). Confirming the value of elastic kinematic analysis, we show that air sac inflation correlates with acoustic markers that likely inform about body size. Finally, we present a pre-processed audiovisual-kinematic dataset of 7+ hours of closeup audiovisual recordings of siamang (Symphalangus syndactylus) singing. This toolkit (https://github.com/WimPouw/AirSacTracker) aims to revitalize the study of non-skeletal morphological structures across multiple species.
Assuntos
Sacos Aéreos , Elasticidade , Animais , Sacos Aéreos/fisiologia , Sacos Aéreos/anatomia & histologia , Fenômenos Biomecânicos , Biologia Computacional/métodos , Aprendizado Profundo , Gravação em Vídeo/métodosRESUMO
Cypermethrin (CYP), a synthetic pyrethroid pesticide, has been detected in agriculture and aquaculture. However, there is limited knowledge about the transgenerational impacts. This study aimed to investigate the developmental toxicity of CYP on F1 larvae offspring of adult zebrafish exposed to various CYP concentrations (5, 10, and 20 µg/L) for 28 days. The results indicated that CYP accumulated in parental zebrafish, and CYP was below the limit of quantification in offspring. Paternal exposure impacted the hatching rate and heart rate of the F1 generation. Furthermore, CYP significantly impacted the development of swim bladders in progeny and dysregulated the genes relevant to swim bladder development. The neutrophil migrated to the swim bladder. The mRNA levels of the inflammatory factors were also significantly elevated. According to network toxicology, PI3-AKT may be the signaling pathway for CYP-influenced bladder development. Subsequent molecular docking and Western blot analysis showed CYP affected the PI3-AKT signaling pathway. Notably, MK-2206, a specific Akt inhibitor, rescued the CYP-induced damage of swim bladder development in offspring. The present study highlights the potential risks of CYP on the development of offspring and lasting impact in aquatic environments.
Assuntos
Inseticidas , Piretrinas , Poluentes Químicos da Água , Peixe-Zebra , Animais , Piretrinas/toxicidade , Poluentes Químicos da Água/toxicidade , Inseticidas/toxicidade , Exposição Paterna/efeitos adversos , Masculino , Feminino , Sacos Aéreos/efeitos dos fármacosRESUMO
Strobilurins, among the most used fungicides worldwide, are considered non-toxic to mammals and birds, but there is growing evidence that these compounds are highly toxic to aquatic species. Dimoxystrobin has been included in the 3rd Watch List of the European Commission, and it has been classified as very toxic to aquatic life. However, previous studies focused on acute toxicity and only two reports are available on its impact on fish, and none on its effects during the early life stages. Here, we evaluated for the first time the effects induced on zebrafish embryos and larvae by two dimoxystrobin sublethal concentrations (6.56 and 13.13⯵g/L) falling in the range of predicted environmental concentrations. We demonstrated that short-term exposure to dimoxystrobin may exert adverse effects on multiple targets, inducing severe morphological alterations. Moreover, we showed enhanced mRNA levels of genes related to the mitochondrial respiratory chain and ATP production. Impairment of the swim bladder inflation has also been recorded, which may be related to the observed swimming performance alterations.
Assuntos
Embrião não Mamífero , Fungicidas Industriais , Larva , Mitocôndrias , Estrobilurinas , Poluentes Químicos da Água , Peixe-Zebra , Animais , Fungicidas Industriais/toxicidade , Larva/efeitos dos fármacos , Estrobilurinas/toxicidade , Mitocôndrias/efeitos dos fármacos , Embrião não Mamífero/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Natação , Sacos Aéreos/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacosRESUMO
Optimization of antioxidants and angiotensin-converting enzyme (ACE) inhibitory potential gelatin hydrolysate production from Labeo rohita (rohu) swim bladder (SBGH) by alcalase using central composite design (CCD) of response surface methodology (RSM) was investigated. The maximum degree of hydrolysis (DH), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), total antioxidants (TAO), and ACE inhibitory activity were achieved at 0.1:1.0 (w/w) enzyme to substrate ratio, 61 °C hydrolysis temperature, and 94-min hydrolysis time. The resulting SBGH obtained at 19.92% DH exhibited the DPPH (24.28 µM TE/mg protein), ABTS (34.47 µM TE/mg protein), TAO (12.01 µg AAE/mg protein), and ACE inhibitory (4.91 µg/mg protein) activity. Furthermore, SBGH at 100 µg/ml displayed osteogenic property without any toxic effects on MC3T3-E1 cells. Besides, the protein content of rohu swim bladder gelatin (SBG) and SBGH was 93.68% and 94.98%, respectively. Both SBG and SBGH were rich in glycine, proline, glutamic acid, alanine, arginine, and hydroxyproline amino acids. Therefore, SBGH could be an effective nutraceutical in functional food development.
Assuntos
Sacos Aéreos , Peixes , Animais , Sacos Aéreos/química , Sacos Aéreos/metabolismo , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Inibidores da Enzima Conversora de Angiotensina/química , Antioxidantes/farmacologia , Antioxidantes/química , Compostos de Bifenilo/química , Cyprinidae/metabolismo , Proteínas de Peixes/metabolismo , Gelatina/química , Hidrólise , Osteogênese/efeitos dos fármacos , Picratos , Hidrolisados de Proteína/química , Hidrolisados de Proteína/farmacologia , Subtilisinas/metabolismo , Peixes/metabolismoRESUMO
Disruption of the thyroid hormone system by synthetic chemicals is gaining attention owing to its potential negative effects on organisms. In this study, the effects of the dio-inhibitor iopanoic acid (IOP) on the levels of thyroid hormone and related gene expression, swim bladder inflation, and swimming performance were investigated in Japanese medaka. Iopanoic acid exposure suppressed thyroid-stimulating hormone ß (tshß), tshß-like, iodotyronin deiodinase 1 (dio1), and dio2 expression, and increased T4 and T3 levels. In addition, IOP exposure inhibited swim bladder inflation, reducing swimming performance. Although adverse outcome pathways of thyroid hormone disruption have been developed using zebrafish, no adverse outcome pathways have been developed using Japanese medaka. This study confirmed that IOP inhibits dio expression (a molecular initiating event), affects T3 and T4 levels (a key event), and reduces swim bladder inflation (a key event) and swimming performance (an adverse outcome) in Japanese medaka.
Assuntos
Sacos Aéreos , Ácido Iopanoico , Oryzias , Natação , Hormônios Tireóideos , Animais , Oryzias/fisiologia , Sacos Aéreos/efeitos dos fármacos , Sacos Aéreos/metabolismo , Hormônios Tireóideos/metabolismo , Hormônios Tireóideos/sangue , Ácido Iopanoico/toxicidade , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Tiroxina/sangue , Tri-Iodotironina/sangue , Iodeto Peroxidase/genética , Iodeto Peroxidase/metabolismoRESUMO
Subterranean organisms provide excellent opportunities to investigate morphological evolution, especially of sensory organs and structures and their processing areas in the central nervous system. We describe the gross morphology of the brain and some cephalic sensory organs (olfactory organ, eye, semicircular canals of the inner ear) and the swim bladder (a non-sensory accessory structure) of subterranean species of pencil catfishes of the genus Ituglanis Costa and Bockmann, 1993 (Siluriformes, Trichomycteridae) and compare them with an epigean species of the genus, Ituglanis goya Datovo, Aquino and Langeani, 2016. We compared qualitatively the size of the different brain regions and sense organs of the subterranean species with those of the epigean one, searching for modifications possibly associated with living in the subterranean environment. Our findings suggest that species of Ituglanis exhibit sensory characteristics that are preadaptive for the subterranean life, as only slight modifications were observed in the brains and sense organs of the subterranean species of the genus when compared with the epigean one. Because most subterranean fish species belong to lineages putatively preadapted for subterranean life, our results, discussed in the context of available information on the brain and sense organs of other subterranean species, help identify general trends for the evolution of the brain and sensory organs of subterranean fishes in general.
Assuntos
Evolução Biológica , Encéfalo , Peixes-Gato , Animais , Peixes-Gato/anatomia & histologia , Peixes-Gato/fisiologia , Encéfalo/anatomia & histologia , Órgãos dos Sentidos/anatomia & histologia , Órgãos dos Sentidos/fisiologia , Adaptação Fisiológica , Sacos Aéreos/anatomia & histologiaRESUMO
BACKGROUND: Sturgeon is a popular aquaculture species in many countries. Its swim bladder is rich in collagen but has not yet been exploited scientifically. RESULTS: Collagen peptides (CPs) prepared from sturgeon swim bladder by trypsinolysis had an average molecular weight of 528.5 Da and consisted of 407 peptides, 16.1% of the content of which was GFPGADGSAGPK. The CPs at 25 mg mL-1 extended the lifespan of Caenorhabditis elegans by 22.6%, which was significantly higher than the extension achieved by other hydrolysis methods and source materials. They also improved fitness-related traits (body size, motor capacity, oxidative stress, cell apoptosis, and epidermal barrier function), indicating prolonged healthspan. Transcriptome analysis showed that the effect was mediated by the mitogen-activated protein kinase pathway, which enhanced stress resistance, the insulin/IGF-1 pathway, which inhibited protein aggregation, and the NHR-80/FAT-6 pathway, which regulated lipid metabolism. CONCLUSION: Collagen peptides from sturgeon swim bladder by trypsinolysis prolonged the lifespan and healthspan in C. elegans, and might be promising anti-aging agents. © 2024 Society of Chemical Industry.
Assuntos
Sacos Aéreos , Caenorhabditis elegans , Colágeno , Peixes , Longevidade , Peptídeos , Animais , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiologia , Longevidade/efeitos dos fármacos , Colágeno/metabolismo , Sacos Aéreos/química , Sacos Aéreos/metabolismo , Peptídeos/farmacologia , Peptídeos/química , Peixes/genética , Estresse Oxidativo/efeitos dos fármacos , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Proteínas de Peixes/químicaRESUMO
Faba bean has gained attention as a cost-effective protein source with the potential to enhance product quality (texture properties, collagen content, etc.) in fish. However, its anti-nutrition factor, high feed conversion ratio, poor growth performance, etc. limit the widely application as a dietary source, especially in carnivorous fish. The water or alcohol extract of faba bean might resolve the problem. In this study, the juvenile Nibea coibor, known for their high-protein, large-sized, and high-grade swim bladder, were fed with seven isoproteic and isolipid experimental diets with the additive of faba bean water extract (1.25%, 2.5%, and 5%) or faba bean alcohol extract (0.9%, 1.8%, and 3.6%), with a control group without faba bean extract. After the 10-week feeding trail, the growth, antioxidant capacity, textural properties, and collagen deposition of the swim bladder were analyzed. Results showed that the 1.25% faba bean water extract group could significantly promote growth, textural quality of the swim bladder, and have beneficial effects on antioxidant response of fish. Conversely, dietary supplementation of faba bean alcohol extract resulted in reduced growth performance in a dose-dependent manner. Furthermore, fish fed diet with 1.25% faba bean water extract exhibited increased collagen content and upregulated collagen-related gene expression in the swim bladder, which was consistent with the Masson stain analysis for collagen fiber. Our results suggested that the anti-nutrient factor and bioactive component of faba bean may mainly be enriched in alcohol extract and water extract of faba bean, respectively. Besides, the appropriate addition of water extract of faba bean may improve the texture quality of the swim bladder by promoting collagen deposition. This study would provide a theoretical basis for the formulated diets with faba bean extract to promote product quality of marine fish.
Assuntos
Sacos Aéreos , Antioxidantes , Colágeno , Dieta , Extratos Vegetais , Vicia faba , Vicia faba/química , Animais , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Colágeno/metabolismo , Antioxidantes/metabolismo , Dieta/veterinária , Ração Animal/análise , Suplementos NutricionaisRESUMO
A 30 years long data series on the infection dynamics of European eel (Anguilla anguilla L.) with the non-native invasive nematode Anguillicola crassus Kuwahara, Niimi & Hagaki, 1974 is presented. Parasite burden was evaluated for 30 years in inland and coastal waters in Mecklenburg-Western Pomerania from 1991 to 2020. The total prevalence, mean intensity and damage status of the swim bladders were very high during the first decade (19912000), and significantly decreased in both marine and freshwater eel populations in the following decades (20012010, 20112020). The parasite intensity of eels in coastal waters was significantly lower compared with the freshwater systems (61.3% vs 79.5% in the first decade), indicating the vulnerability of the parasites to brackish water conditions and the fact that the life cycle of A. crassus cannot be completed under high saline conditions. Eel caught in the western part of the Baltic Sea (west of Darss sill) had the lowest mean infection (51.8% in first decade) compared to the eastern part with 63.8%. Thus, besides different infection patterns caused by the environmental conditions, a temporal trend towards a reduced parasite intensity and a more balanced parasitehost relationship developed in the 30 years of interaction after the first invasion. Possible reasons and mechanisms for the observed trends in parasitehost interactions are discussed.
Assuntos
Anguilla , Dracunculoidea , Doenças dos Peixes , Animais , Anguilla/parasitologia , Sacos Aéreos/parasitologia , Estágios do Ciclo de Vida , Alemanha/epidemiologia , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/parasitologiaRESUMO
Pulmonary aspergillosis occurring in captive penguins living in zoos and aquariums is a fatal disease owing to its high mortality rate. On conducting computed tomography, two gentoo penguins (Pygoscelis papua) with respiratory clinical signs that were housed at an aquarium in Hokkaido, Japan were found to have a certain amount of fluid in their air sacs. This fluid was collected and cultured for bacteria and fungi, the results of which both came back negative. These results enabled us to rule out bacterial infection or aspergillosis and supported our decision not to administer antibacterial and antifungal drugs. Overall, the combination of computed tomography and air sac fluid examination was useful for ruling out bacterial infection or aspergillosis in penguins with respiratory clinical signs.
Assuntos
Aspergilose , Infecções Bacterianas , Spheniscidae , Animais , Sacos Aéreos , Aspergilose/diagnóstico por imagem , Aspergilose/veterinária , Tomografia Computadorizada por Raios X/veterinária , Infecções Bacterianas/veterináriaRESUMO
A macrourid, Coryphaenoides yaquinae sp. inc., was observed to be attracted to bait and exhibiting normal foraging behaviour during a period of 80â min within view of a baited video camera on the sea floor at 7259â m - the deepest ever observation of a fish species with a swim bladder. The buoyancy provided by an oxygen-filled swim bladder at 74.4â MPa pressure was estimated to be 0.164 N, at a theoretical energy cost of 20â kJ, 200 times less than the cost of equivalent lipid buoyancy. During normal metabolism, 192â days would be required to fill the swimbladder. At these depths, oxygen is very incompressible, so changes in volume during ascent or descent are small. However, swimbladder function is crucially dependent on a very low rate of diffusion of oxygen across the swimbladder wall. The oxygen in the swimbladder could theoretically sustain aerobic metabolism for over 1 year but is unlikely to be used as a reserve.
Assuntos
Sacos Aéreos , Peixes , Animais , Japão , Peixes/metabolismo , Oxigênio/metabolismoRESUMO
One of the most remarkable features in sauropod dinosaurs relates to their pneumatized skeletons permeated by a bird-like air sac system. Many studies described the late evolution and diversification of this trait in mid to late Mesozoic forms but few focused on the origin of the invasive respiratory diverticula in sauropodomorphs. Fortunately, it is possible to solve this thanks to the boom of new species described in the last decade as well as the broad accessibility of new technologies. Here we analyze the unaysaurid sauropodomorph Macrocollum itaquii from the Late Triassic (early Norian) of southern Brazil using micro-computed tomography. We describe the chronologically oldest and phylogenetically earliest unambiguous evidence of an invasive air sac system in a dinosaur. Surprisingly, this species presented a unique pattern of pneumatization in non-sauropod sauropodomorphs, with pneumatic foramina in posterior cervical and anterior dorsal vertebrae. This suggests that patterns of pneumatization were not cladistically consistent prior to the arrival of Jurassic eusauropods. Additionally, we describe the protocamerae tissue, a new type of pneumatic tissue with properties of both camellae and camerae. This reverts the previous hypothesis which stated that the skeletal pneumatization first evolved into camarae, and derived into delicate trabecular arrangements. This tissue is evidence of thin camellate-like tissue developing into larger chambers. Finally, Macrocollum is an example of the gradual evolution of skeletal tissues responding to the fastly specializing Respiratory System of saurischian dinosaurs.
Assuntos
Sacos Aéreos , Dinossauros , Animais , Evolução Biológica , Dinossauros/anatomia & histologia , Microtomografia por Raio-X , Fósseis , FilogeniaRESUMO
An unmanned surface vehicle (USV; Wave Glider) was deployed to study the coastal soundscape in shallow (less than 30 m) coastal waters off the coast of Cape Canaveral, FL, in July 2020 and January 2022. These surveys documented temporal and seasonal trends in biological sounds across a variety of habitats within an 812-km2 survey area, including sand shoals, sand-mud plains, and natural hardbottom. Among a broader diversity of identifiable and unidentifiable fish choruses recorded during the survey, a distinct and previously unidentified fish chorus was recorded; corroborating evidence suggests it and other sounds with similar spectral properties may be produced by Atlantic midshipman. Putative Atlantic midshipman sounds included an agnostic grunt and a seasonal chorus of persistent hums that peaked 3 h after sunset in the summer survey. While Atlantic midshipman have been demonstrated to have well-developed sonic muscles on their swim bladder, their acoustic behavior has not been previously described. Our use of a mobile passive acoustic platform combined with bottom sampling of fish communities highlights an important opportunity to identify previously undocumented biological sound sources in coastal habitats.
Assuntos
Batracoidiformes , Animais , Areia , Acústica , Sacos Aéreos , AeronavesRESUMO
Hearing evolved in lampreys with a frequency range of 50-200 Hz. This hearing range is comparable to that of elasmobranchs, most non-teleosts, and lungfish. Elasmobranchs most likely use the saccule and the papilla neglecta (PN) for hearing. In non-teleosts and teleosts, lungfish, and certain tetrapods the saccule is the likely sensor for sound reception while the lagena and the PN are important for gravistatic sensing. Coelacanth and most tetrapods have a basilar papilla (BP) for hearing. In coelacanth and tetrapods, the hair cells of the BP are in contact with a basilar and a tectorial membrane. These membranes transmit mechanical vibrations. A cochlear aqueduct (CA) provides a connection between the cerebrospinal fluid that has a sodium rich space in coelacanth and tetrapods while the potassium rich endolymph is known in vertebrates. A unique feature is known in basic sarcopterygians, the intracranial joint, that never developed in actinopterygians and has been lost in lungfish and tetrapods. The BP in coelacanths is thought to generate pressure with the intracranial joint that will be transmitted to the CA. Lungs or a swim bladder are not forming in Chondrichthyes, structures that have a major impact on hearing in teleosts and tetrapods.
Assuntos
Peixes , Audição , Animais , Som , Sacos Aéreos , Células Ciliadas AuditivasRESUMO
The six species of lungfish possess both lungs and gills and are the closest extant relatives of tetrapods. Here, we report a single-cell transcriptome atlas of the West African lungfish (Protopterus annectens). This species manifests the most extreme form of terrestrialization, a life history strategy to survive dry periods that can last for years, characterized by dormancy and reversible adaptive changes of the gills and lungs. Our atlas highlights the cell type diversity of the West African lungfish, including gene expression consistent with phenotype changes of terrestrialization. Comparison with terrestrial tetrapods and ray-finned fishes reveals broad homology between the swim bladder and lung cell types as well as shared and idiosyncratic changes of the external gills of the West African lungfish and the internal gills of Atlantic salmon. The single-cell atlas presented here provides a valuable resource for further exploration of the respiratory system evolution in vertebrates and the diversity of lungfish terrestrialization.
Assuntos
Ascomicetos , Salmo salar , Animais , Aclimatação , Sistema Respiratório , Brânquias , Sacos AéreosRESUMO
The lack of data on the species-specific Target Strength (TS) on ancillary species limits the application of acoustic surveys in assessing their abundance and distribution worldwide. The TS values of Scomber colias and Trachurus mediterraneus in use in the Mediterranean Sea rely on studies conducted on other species in the Atlantic and Pacific oceans. Nevertheless, the application of backscattering models offers the possibility to overcome the absence of empirical data handling the parameters that most affect the TS. X-ray scans were performed on 82 specimens to get digital representations of the swimbladder and the fish body which were used as input for the application of the Kirchhoff Ray Mode model to measure the TS as a function of frequency and tilt angle. The morphometric differences between the two species produced divergent relative frequency responses and broadband TS patterns. Moreover, comparing the results with one ex-situ experiment, we found a good agreement considering a mean tilt angle of - 10°, standard deviation = 12°. Our results provide the first theoretical insights into the use of backscattering models as a tool to distinguish between species in the Mediterranean Sea by acoustic method, increasing the knowledge of the acoustic reflectivity of ancillary species.
Assuntos
Acústica , Peixes , Animais , Sacos Aéreos , Conhecimento , Mar MediterrâneoRESUMO
Air sac cannulation is used both as an emergency procedure in avian patients with severe upper respiratory compromise, as well as a means of routine ventilation for surgery of the head and neck. The objective of this retrospective study was to describe and quantify the complications associated with air sac cannulation in birds. Medical records were retrieved for all patients that underwent caudal thoracic or abdominal air sac cannulation at a single center between August 2004 and October 2020. Patient signalment, indication for air sac cannulation, location of air sac cannula (ASC) placement, occurrence and category of complications encountered, and survival data were recorded. Eighty-four ASCs were placed in 68 birds across 6 orders; 95.2% (80/84) of cases survived general anesthesia for initial ASC placement. The side and position of ASC placement were known in 33.3% (28/84) and 21.4% (18/84) of cases, respectively. Survival to ASC removal was known in 91.3% (73/80) of cases; 43 (58.9%) of these 73 cases survived to ASC removal. Complications were observed in 32.5% (26/80) of cases, and 11.5% (3/26) of cases died as a direct result of the complication. The most common reported ASC complication was loss of patency in 23.8% (19/80) of cases. Increased likelihoods for complications were seen in cases where exercise intolerance (P = 0.04) or abnormal respiratory sounds (P = 0.04) were reported at presentation. Increased likelihoods for survival to ASC removal were seen with intercostal placements (P = 0.049) and peri-interventional antibiotic therapy (P = 0.005). Decreased likelihood for survival to ASC removal was seen in cases where voice change was reported at presentation (P = 0.02). This study demonstrates a moderate risk of ASC complication, with a guarded overall prognosis for survival to ASC removal.
Assuntos
Sacos Aéreos , Aves , Animais , Estudos Retrospectivos , Registros/veterinária , Cateterismo/veterináriaRESUMO
One possible reason for the European eel (Anguilla anguilla) population decline is the neozoan eel swim bladder nematode Anguillicola crassus. To investigate whether the prevalence of A. crassus and the associated swim bladder pathology is related to eel habitat, growth rate, and age, 728 yellow eels from 6 habitats differing in salinity and located along the German Baltic coast were examined between 2005 and 2009. The prevalence of A. crassus varied between habitats, ranging from 9 to 57%. Infection prevalence and the percentage of eels with a damaged swim bladder were significantly higher in inner coastal waters compared to more saline open coastal water. In infected eels, 1 to 32 adult and preadult individuals of A. crassus were observed. The mean infection intensity varied between habitats from 2 to 7 nematodes per eel but did not significantly differ between inner and open coastal waters. Infection prevalence and intensity decreased significantly with age when all open coastal waters and all habitats were combined. Both the lower prevalence of A. crassus and the swim bladder damage of older eels and of eels originating from open coastal water habitats suggest that these eels have a higher fitness for spawning migrations than eels from inner coastal waters. The present study underlines the importance of eel screening on a sufficiently small geographical scale for the accurate estimation of eel recruitment and the identification of priority areas that are likely to produce healthy silver eels.
Assuntos
Anguilla , Dracunculoidea , Doenças dos Peixes , Animais , Bexiga Urinária , Doenças dos Peixes/epidemiologia , Sacos Aéreos , Ecossistema , ÁguaRESUMO
Air sac trematodes (Digenea: Cyclocoelidae) were detected in 23 avian species from eight aviaries in the United States. Most of the infected host species were passeriform birds, but a few species in other orders also were infected. Four species of adult flukes were encountered: Circumvitellatrema momota, Morishitium sp., Psophiatrema greineri, and Szidatitrema yamagutii. Findings from retrospective review of medical records, necropsy records, and author observations are presented. Potential terrestrial snail intermediate hosts were collected from three indoor aviaries. A high prevalence (47%) of larval trematode infections was demonstrated in one species of nonnative snail (Prosopeas achatinacea); one larva was isolated and matched to the adult species (C. momota) from birds using PCR. Problems with introducing potentially infected wild-caught birds into aviaries, and exchanging captive individuals between aviaries where they potentially may carry infections, are discussed.
Assuntos
Trematódeos , Infecções por Trematódeos , Animais , Estados Unidos/epidemiologia , Sacos Aéreos , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/veterinária , Aves , Larva , CaramujosRESUMO
Parasites negatively affect biological processes within their hosts, which may alter for example health, growth, and reproductive ability. Non-native invasive parasites, in particular, may have large effects on the endemic hosts, given that the hosts lack evolved specific defences against such parasites. The swim bladder nematode Anguillicola crassus, an invasive parasite originating from Asia, is found in the European eel (Anguilla anguilla, L. 1758), since the 1980s. We investigated whether A. crassus affected several indicators related to health of the European eel (spleen- and liver size, body fat content and relative condition). Our results indicate that during the continental residency of the eels, infection by A. crassus had no major negative impacts on the investigated health indicators at the generally low infection intensities present in this study (median 2-3 visible parasites). Given that many of the adult eels were found to have swim bladder damage, concerns about their spawning migration through deeper oceanic environments can still be raised. To allow further investigations, we suggest that quantification of swim bladder damage should be implemented in eel-monitoring programs. Compared to other parasite pressure parameters, swim bladder damage provides additional information about past infections and future problems.